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NCEP does not provide this information to WDQMS (that is why it is shown as Type: n/a) as they don't currently pass info into their DA database on whether the observation source was TAC or BUFR. However, most data NCEP uses is TAC.
Why does DWD surface availability maps always show less observations than ECMWF for example, with orange dots being the dominant feature?
The quality monitoring information provided by the four NWP Centres (DWD, ECMWF, JMA and NCEP) is based on the feedback from their data assimilation (DA) system, therefore reflect their specific characteristics. DWD DA does not have the model background available for the observations they do not intend to assimilate, whereas ECMWF calculates the model background for all the observations made available to DA, even for the ones that the model is not supposed to use in the assimilation (e.g. observations from stations that are in the blacklist due to known poor quality). The frequency at which the observations are used within each assimilation window (i.e. 3-hourly at DWD and hourly at ECMWF) explains the discrepancy seen in the number of received by DWD (2 in 6-hour interval) and ECMWF (6 in a 6-hour interval).
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